This is an interactive Flash lesson based on Punnett squares and basic genetics. Students will use their knowledge of dominant and recessive alleles (see "Dominant versus Recessive Gene Gizmo) in order to breed albino lemming using specific traits. The LP I created which includes the activity is also included:
[Adobe Shockwave(r) software is required]
http://www2.edc.org/weblabs/Punnett/punnettsquares.html